For the "twinkle" to twinkle you have to remember to hit the button in the previous level "which button" and leave the room dark.

For the glass, hold down on the "glass" pieces one at a time. If you hold down the mouse for about 3 or 4 seconds, the real glass will break.

For the counterclockwise, simple answer is the one that spins when you click on its right half. Long answer, imagine you are looking at the spinning disks from above. The one that is spinning in the counterclockwise direction is the correct one. The hardest part is correctly identifying the direction of the spinning.

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Level 1The circles are actually cones and cylinders, their true nature visible by dragging the bottom edge up. The cone-shaped ones are the correct ones.

Level 2The circles open their eyes when moused over. The correct circle will open its mouth and scream at the cursor when clicked on.

Level 3Because the correct circle is actually a shadow, the cursor darkens when inside.

Level 4That's "minute" as in "small", not "minute" as in "60 seconds". The circles move choppily when dragged. The correct circle is the one that makes smaller "jumps".

Level 5Dragging across a circle makes multicolored scratches. The correct circle is rotating quickly, which makes the scratches look like multicolored circles.

Level 6The circles rest on a plane; drag up to reveal the truth. The correct circle is the one that's further away (it's bigger so it looks the same size from that distance).

Level 7Each circle is a swinging cover that can be dragged around and up. The correct circle has a blue button behind it that turns the lights on and off when clicked. TURN THE LIGHT OFF BEFORE MAKING YOUR CHOICE!

Level 8This one's either easy or impossible, depending on your preparations. If you left the lights off when you inspected the level 7 circles, the correct circle will light up when moused over. If you didn't, they're indistinguishable, requiring you to pick one and cross your fingers.

Level 9The circles are lenses. Drag them over the text. Concave lenses make things appear smaller; convex, bigger. Thus, the one that makes the text appear smaller is correct.

Level 10The circles shrink when clicked and held. The correct one is the one that shrinks faster.

Level 11The circles are hard circles concealed in fluffy shells that make them look the same size. Poke them gently with the cursor; the fluffy shell on the correct circle won't give as much.

Level 12To test the circles, drag the ceiling down to squash them. The correct circle will spring back to shape when the ceiling is raised; the incorrect circle won't.

Level 13The glass used to make the correct circle is fragile. Hold the mouse over each one for a second or so; the correct one will crack.

Level 14Drag both circles. The correct one will leave a trail.

Level 15The correct circle is a display screen; the incorrect one is a camera. When you mouse over the incorrect circle, your cursor will be displayed on the correct one.

Level 16That's "counterclockwise" as seen from above. Each circle will freely spin if clicked, but only in one direction. The correct circle will spin only if its right half is clicked, and halt if its left half is clicked; the incorrect circle, vice-versa.

Level 17Be careful! The circles are superimposed on inverted space. The correct circle is the one that says "Right" when moused over. For the purposes of matching the buttons to the circles, ignore the reversal.

Level 18The circles are pendulums on invisible chains. Drag them up and watch them swing. The correct circle's swing has a sharper arc, created by a shorter chain. It also swings more quickly.

Level 19Drag left and right. The correct circle will have stars and changes of color visible inside it.

Level 20Not to be confused with "Which Do Not Press?", although the principle is similar. When you mouse over either circle, the text will become jittery and the screen will flash red. If it's the incorrect circle, it'll stop after two or three seconds; if it's the correct circle, it won't, but pick fast before the screen explodes!